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문제You are given an n x n 2D matrix representing an image, rotate the image by 90 degrees (clockwise).You have to rotate the image in-place, which means you have to modify the input 2D matrix directly. DO NOT allocate another 2D matrix and do the rotation.예시Example 1.Input: matrix = [[1,2,3],[4,5,6],[7,8,9]] Output: [[7,4,1],[8,5,2],[9,6,3]] Example 2.Input: matrix = [[5,1,9,11],[2,4,8,10],[13,3,..

문제You are given the head of a singly linked-list. The list can be represented as:L0 → L1 → … → Ln - 1 → LnReorder the list to be on the following form:L0 → Ln → L1 → Ln - 1 → L2 → Ln - 2 → …You may not modify the values in the list's nodes. Only nodes themselves may be changed.예시Example 1: Input: head = [1,2,3,4] Output: [1,4,2,3] Example 2: Input: head = [1,2,3,4,5] Output: [1,5,2,4,3]조건The num..

문제You are given an array of k linked-lists lists, each linked-list is sorted in ascending order.Merge all the linked-lists into one sorted linked-list and return it.예시Example 1:Input: lists = [[1,4,5],[1,3,4],[2,6]] Output: [1,1,2,3,4,4,5,6] Explanation: The linked-lists are: [ 1->4->5, 1->3->4, 2->6 ] merging them into one sorted list: 1->1->2->3->4->4->5->6Example 2:Input: lists = [] Out..

문제Given head, the head of a linked list, determine if the linked list has a cycle in it.There is a cycle in a linked list if there is some node in the list that can be reached again by continuously following the next pointer. Internally, pos is used to denote the index of the node that tail's next pointer is connected to. Note that pos is not passed as a parameter.Return true if there is a cycle..

문제Given an array of intervals intervals where intervals[i] = [start_i, end_i], return the minimum number of intervals you need to remove to make the rest of the intervals non-overlapping.Note that intervals which only touch at a point are non-overlapping. For example, [1, 2] and [2, 3] are non-overlapping.예시Example 1:Input: intervals = [[1,2],[2,3],[3,4],[1,3]] Output: 1 Explanation: [1,3] can b..

문제You are given an array of non-overlapping intervals intervals where intervals[i] = [start_i, end_i] represent the start and the end of the ith interval and intervals is sorted in ascending order by starti. You are also given an interval newInterval = [start, end] that represents the start and end of another interval. Insert newInterval into intervals such that intervals is still sorted in asce..

문제Given an unsorted array of integers nums, return the length of the longest consecutive elements sequence.You must write an algorithm that runs in O(n) time.예시Example 1:Input: nums = [100,4,200,1,3,2] Output: 4 Explanation: The longest consecutive elements sequence is [1, 2, 3, 4]. Therefore its length is 4. Example 2:Input: nums = [0,3,7,2,5,8,4,6,0,1] Output: 9Example 3:Input: nums = [1,0,1,..

문제There are a total of numCourses courses you have to take, labeled from 0 to numCourses - 1. You are given an array prerequisites where prerequisites[i] = [a_i, b_i] indicates that you must take course b_i first if you want to take course a_i.For example, the pair [0, 1], indicates that to take course 0 you have to first take course 1.Return true if you can finish all courses. Otherwise, return..